PREKONSENTRASI Au(III) DENGAN MERKAPTO-SILIKA TERLAPIS PADA MAGNETIT; PRECONCENTRATION OF Au(III) WITH MERCAPTO-SILICA COATED ON MAGNETITE

Cucun Alep Riyanto, Nuryono

2014 | Disertasi | PROGRAM STUDI S2 ILMU KIMIA

In this research, preconcentration of Au(III) with mercapto-silica coated on magnetite (MSCM) has been studied. The MSCM was synthesized by sol gel process with sodium silicate solution (Na2SiO3) from rice husk ash as silica sources and 3-(trimethoxyisilyl)-1-propanethiol (TMSPT) as mercapto group (- SH) sources in the presence of magnetite. Characterization for MSCM was performed with Fourier Transformed Infrared (FTIR), X-ray Diffractometer (XRD), and Transmission Electron Microscope (TEM). The study on sorption of Au(III) in AuCl4 - solution was carried out with a batch system and the desorption of Au(III) was conducted with leaching agent such as thiourea in hydrochloride acid and sodium thiosulphate solution. The preconcentration of Au(III) was carried out on dilute solution of AuCl4 - to more concentrate solution of AuCl4 - at final solution. The amount of Au(III) was adsorbed on MSCM calculated with Atomic Absorption Spectrometry (AAS). The research resulted the particle size of MSCM was around 17-19 nm with the adsorption capacity of Au(III) was 124.76 mg/g with the energy of adsorption was 26.98 kJ/mol. The adsorbed Au(III) could be desorbed 57.90 mg/L from MSCM with 0.1 mol/L HCl solution containing 3.5% (w/v) of thiourea. The preconcentration of Au(III) was done with leaching agent as solution of 3% (w/v) thiourea in 0.1 mol/L HCl. A preconcentration factor of 8 were obtained for Au(III) by MSCM. The MSCM could be used up to five times of reuse without changing the performance with the adsorption capacity keep steady at about 60 mg/g.

Kata Kunci : adsorption, desorption, mercapto, silica, magnetite, preconcentration, and reuse.